Last month I wrote about an advert from Smart Energy GB promoting the current smart metering programme. The headline was that by having a smart meter installed you could save enough energy to charge your mobile phone for 177 years. It’s a good headline to attract people’s attention, but it seemed high. I was intrigued and decided to try and work out where that number had come from? I found that the calculation was riddled with mistakes and that a more realistic analysis showed that the saving was equivalent to charging it for just 17 years. I’ve since realised that even that figure was optimistic and in fact it’s just 16 years.

A reader kindly informed me that Smart Energy GB has produced a wider series of these adverts and have published how they calculated the claims. They obviously think they understand what they’re doing, as they’ve put the basis of their calculations on their website. (In case they change them after reading this, I’ve archived the version that was on their website when I wrote this article at http://bit.ly/dumbenergyGB.) Their webpage explains the workings behind seven adverts and in every single case they’ve got their calculations wrong. The mistakes range from a failure to understand how battery charging works, an inability to calculate percentages, getting formulas wrong, misreading much of their source data, including mistaking 2 x 12 for 212, not understanding the context of their source data or realising that electricity and gas have markedly different prices.

Most of the adverts overestimated the savings, but a few underestimated them. So, there was probably no deliberate attempt to mislead. Just an unbelievable level of incompetence. But we mustn’t fall into believing this type of fake data. Once we stop questioning, we set the scene for Orwellian manipulation.

The table below summarises the mistakes in each advert. In the remainder of this article I will detail the exact problems, along with each calculation. Please feel free to forward this information to your MP, asking them to forward it to the minister concerned and requesting an answer on how this level of incompetence has been allowed and how much money has been wasted in disseminating it.

It’s a shockingly bad performance, but is symptomatic of the sloppy thinking which surrounds the whole smart metering campaign. Smart Energy GB have received over £190 million from DECC and BEIS to fund the overall marketing campaign, so they can’t claim that they cannot afford to check the figures – these are all schoolboy mistakes. These aren’t even good adverts. The whole economic case for smart metering in Britain is based on consumer savings, claiming that if people can see what they spend on energy, they will change their behaviour. Yet nowhere do these adverts point out what the savings actually are – charging your phone for 177 years or riding 1,112 miles in your mobility scooter are too intangible and totally miss the message of behaviour change, not least as they imply that you can do something else with the energy you save, with the end result that you save no energy. It smacks of desperation as the whole smart metering programme realises it is not going to meet its target of getting a smart meter in every home by the end of 2020. All they are doing is throwing taxpayers’ money away.

Given that these advertisements are in the national press, numerous other print publications, on bus hoardings, tube trains, radio and TV, I’d guess that they have spent at least £50 million on the current campaign, yet every single advert is wrong. It is a litany of fake headlines. I’ve submitted Freedom of Information requests to try to find out how much taxpayer’s money has been spent on this mis-information, but have not yet had any reply.

Here’s how wrong their claims are:

These mistakes are inexcusable. I have reported these adverts to the Advertising Standards Authority. I’ve also sent a copy of this article to my MP and asked her to raise my concerns with the minister responsible regarding the incompetence of Smart Energy GB and the appalling cost to the taxpayer of this misinformation campaign. I urge you to do the same. The remainder of this article explains the details of what is wrong with each advert. I apologise for repetition – I’ve documented each advert as a stand-alone example, so you can cut and paste them into the ASA complaints form, which you can find at www.asa.org.uk/make-a-complaint.html. If you need a copy of each advert to attach, just click on the title of the description. I’ve uploaded them with dates of publication.

Let me make one final observation. For the cost of running Smart Energy GB, you could probably have bought three 7W LED bulbs for every man, woman and child in the UK. If everyone replaced three existing 50W halogen bulbs with these free LED bulbs, and used them for 8 hours a day, that would save the average home £123 per year, over five times the savings they would get from reducing their energy usage by 2%. Instead of which we’ve poured that money down the drain by giving it to a group of innumerate “creatives” who are trying to prop up an untenable smart metering programme. Read on and weep.

This Smart Energy GB advert looks at how the savings an average household would make could be used to charge a tablet, allowing their child to play the same song for ten hours every night until they reach the age of 36. They have miscalculated – You would only be able to charge it for 4 years.

Their first problem is that they don’t understand how battery charging works. They take the energy capacity of an iPad battery (0.0275 kWh) and assume the battery and charging is 100% efficient. Real life is different.

Their figure for the energy capacity is for a 2012 model – more recent ones have a slightly larger capacity of 0.0304 kWh. However, that capacity has been arrived at based on the battery output voltage, which is 3.7V, i.e. it is a 7.306 Ah battery. Smart Energy GB have missed the point that it’s charged from a 5V USB supply, so the energy needed to charge it is 7.306 Ah x 5V, which is 0.0365 kWh, not 0.0275 kWh. Some tablets use a buck converter to make this more efficient, but there are invariably other inefficiencies such as over-charging, so it’s probably still optimistic.

They also assume that the charger is 100% efficient – in practice they are around 90% efficient and also assume that every joule of energy that goes into a battery comes back out. It doesn’t. Typically, you need to put in at least 110% of the battery capacity to get that energy out. As the battery degrades that efficiency falls, so for longer term use you should only consider it to be 85% efficient. Factoring these in, and being very optimistic, the energy needed to charge the tablet each day so that it plays for ten hours every night is 0.049 kWh, not Smart Energy GB’s 0.027 kWh. For a more recent iPad, that figure is 0.0537 kWh.

The second problem is that they assume that energy savings will be made equally on electricity and gas. (In this they follow BEIS’s view, although there is no evidence that smart meters help consumers save gas.) If we exclude gas savings, the energy saved would be restricted to the annual average household electricity usage of 3,889 kWh. 2% of that is 77.8 kWh. The annual consumption of a modern iPad is 5.37 x 365 Wh, which is 19.6 kWh if you charge it once a day for a year. Compare that to the overall 77.8kWh saving and you’ll only be able to charge it for 4 years, not the 35 years that Smart Energy GB claim. In other words, they’re exaggerating by almost a factor of ten.

In the unlikely case that users did save energy by reducing their gas consumption, Smart Energy GB still get their figures wrong. To the best of my knowledge, no company sells a gas-powered iPad charger, so the money saved from any gas savings would need to be used to buy electricity. Smart Energy GB’s calculations forget that electricity is more expensive than gas. One kWh of gas costs around 4.4 pence, depending on where you live, whereas for electricity it costs about 13p. The money you would save from a 2% reduction in gas usage would only buy you an additional 93.4 kWh of electricity, not the 276 kWh that Smart Energy GB use in their calculation. So, if you save gas as well as electricity (which you almost certainly won’t), you’d only be able to purchase enough energy to charge your iPad for 8.7 years.

Smart Energy GB also forget to mention that you will only have a hope of saving energy if you use the In Home Display that is supplied with the smart meter. These can consume up to 0.6W, which is 14.4 Wh per day, or 5.26 kWh per year. This is additional electricity usage you pay for whether or not you make any savings. This means that the real electricity saving is only 72.5 kWh per year, which would only run your iPad through the night for 3.7 years. That is very much less than their estimate of 35 years. The calculation also ignores the fact that whilst babies may sleep for ten hours a night, teenagers and adults don’t, so it doesn’t address reality. Although I suspect the sleepy heads at Smart Energy GB may well spend most of their lives asleep.

This Smart Energy GB advert looks at how the savings an average household might make by having a smart meter could be used to charge a mobility scooter. They calculate it would run for 1,112 miles on that saved energy. The correct figure is 1,170 miles. Although that is a small discrepancy, they arrive at their number by pure luck, as almost all of their calculations are wildly wrong. In the process they demonstrate that they cannot even copy a number correctly from a webpage.

Smart Energy GB start off by stating the battery size of a typical mobile scooter. Here they make their first mistake. They refer to the specification on the Roma Mobility Scooter website, which states that it contains two 12Ah batteries. Unfortunately, Smart Energy GB have misread 2 x 12 Ah as a single 212Ah battery. That means they start with a battery almost nine times bigger than it actually is.

As with their other adverts, they don’t understand how battery charging works. They take their incorrect 212Ah figure, multiply it by the battery voltage of 12V and assume the battery and charging is 100% efficient. The actual charging process for the sealed ATM/Gel batteries used in these scooters is more complex, starting at 14.4V, before moving to a constant current regime, where the voltage falls. If we assume a decent charger, it should have an efficiency of around 80%. Factoring these points in, the energy needed to charge the battery is about 0.43kWh. As Smart Energy mistakenly thought the battery capacity was 212 Ah instead of 24 Ah, they estimate that it needs 2.54 kWh – six times more.

The second mistake is that they assume that energy savings will be made equally on electricity and gas. (In this they follow BEIS’s view, although there is no evidence that smart meters help save gas.) If we exclude gas savings, the energy savings should be restricted to the annual household average electricity usage of 3,889 kWh. 2% of that is 77.8 kWh, and if we divide that by 0.43 kWh we see that the battery could be charged 180 times. As each charge runs the scooter for 8 miles, that equates to 1,440 miles.

In the unlikely case that users did save energy by reducing their gas consumption, Smart Energy GB still get their figures wrong. To the best of my knowledge, no company sells a gas-powered mobility scooter charger, so the money saved by adding in gas savings would need to be used to buy electricity. Smart Energy GB’s calculations forget that electricity is more expensive that gas. One kWh of gas costs around 4.4 pence, depending on where you live, whereas for electricity it costs about 13p. The money you would save from a 2% reduction in gas usage would only buy you an additional 93.4 kWh, not the 276 kWh that Smart Energy GB use in their calculation. If you save gas as well as electricity (which you almost certainly won’t), you’d be able to purchase enough energy to run your scooter for 3,170 miles – still different from Smart Energy GB’s miscalculation of 1,112 miles.

Smart Energy GB also forget to mention that you will only have a hope of saving energy if you use the In Home Display that is supplied with the smart meter. These can consume up to 0.6W, which is 14.4 Wh per day, or 5.26 kWh per year. This is additional electricity usage you pay for whether or not you make any savings. This means that the real electricity saving is only 72.5 kWh per year, so you would only be able to run your mobility scooter for 1,343 miles

Smart Energy GB’s figure of 1,112 miles is close only because their two mistakes – including spurious gas savings and misreading the battery capacity fortuitously cancel each other out. If they hadn’t misread the battery data, their calculation would have come up with a figure of 9,828 miles instead of the lower 1,112 miles.

This Smart Energy GB advert looks at how the savings which an average household might achieve from having a smart meter could be used to bake 236 cakes. It ignores the fact that if you baked 236 additional cakes, you would not have saved any energy – you would just get fat and impose an additional burden on the NHS. However, ignoring the mixed message, the underlying calculation is wrong. It also cites a source which is clearly marked as “This electronic copy is provided, free, for personal use only”, so they are infringing copyright as well as being unable to add up.

For their baking cakes advert, Smart Energy GB demonstrates that they can’t read, or at least, can’t understand what they’re reading. They quote the late David MacKay’s excellent book on Renewable Energy – Sustainable Energy – without the hot air, which cites that an electric oven on full power consumes 3kWh per day. On average, he reckons an oven is used for half an hour per day, which comes to 1.5kWh. That’s equivalent to 30 minutes of use at 240°C. Smart Energy GB misread that figure as the hourly rate, so their calculation starts out by being wrong by a factor of two. Incidentally, the source they quote is the free download of David’s book, which is clearly marked “Copyright David JC MacKay 2009. This electronic copy is provided, free, for personal use only”. It’s a bit naughty to reference this version – Smart Energy GB have more than enough money to buy a real copy. I suspect it may also be illegal.

You’d think that Smart Energy UK might have learnt something from eight years of Mary Berry and the Great British Bake Off, as they’re certainly not spending their evenings brushing up on their maths skills, but apparently not. They miss the fact that the 1.5 kWh per 30 minutes figure is for full power, which corresponds to having the oven at 240°C. Unless you’re doing a King Alfred and want them black, cakes are generally baked between 160°C and 180°C, not 240°C, so the oven will only consume about half that amount of power.

An average baking time for a cake is 45 minutes, which means that baking each cake needs 1.125kWh, not 1.5kWh. Their figure is not too far out, but that’s because they’ve made two mistakes which fortuitously cancel each other out.

However, there’s a bigger problem, which is that you almost certainly won’t save energy on your gas bill. There is some evidence that smart meters help save electricity, because you get an almost immediate indication of energy usage. The favourite example is showing how much your kettle uses, which is a good reinforcement prompt to remind you to reduce the amount of water you boil. For gas, you only get told the amount of energy used every half hour, so you won’t know whether it was used by the oven for baking the cake, hot water for clearing up the mess in the kitchen afterwards or from heating the house. Without a clear connection between cause and effect, there’s no nudge to promote behavioural change. Yet BEIS and Smart Energy GB keep on insisting that gas savings will happen, despite a dearth of evidence from anywhere else in the world. So we should ignore any gas saving.

If the household saves 2% on their electricity usage, they could spend this on energy to bake cakes. As electricity and gas have different costs, those 2% savings on electricity would buy them 78kWh of electricity resulting in 69 cakes if they have an electric oven, or 229kWh of gas giving them 204 cakes in a gas oven. Both of which are significantly lower than the 255 cakes which Smart Energy GB quote.

Smart Energy GB also forget to mention that you will only have a hope of saving energy if you use the In Home Display that is supplied with the smart meter. These can consume up to 0.6W, which is 14.4 Wh per day, or 5.26 kWh per year. This is additional electricity usage you pay for whether or not you make any savings. It means that the real electricity saving is only 72.5 kWh per year, so you would only be able to bake an additional 64 cakes. The cost of running the In Home Display for a year is an equivalent cost to consuming 15.5 kWh of gas, which, if you factor that in, means you’d only have saved enough to cook 190 cakes.

Smart Energy GB also don’t seem to realise that you can cook two or even three cakes at the same time. Telling people to cook just one at a time is not a very good lesson if you’re trying to educate people to save energy, which is what this advert is meant to be about.

Incidentally, I think that David MacKay’s book is one of the best books on energy around and I’d suggest everyone interested in the subject should have a copy on their bookshelf. David wrote it to expose the fluffy thinking that often goes around energy policy and would probably have seen this current advertising campaign by Smart Energy GB as further evidence of the inability of those involved with policy to add two and two together.

This Smart Energy GB advert looks at the savings an average household could achieve from having a smart meter and tries to calculate how many baths you could run with the amount of saved energy. Their calculations are wrong, because they use incorrect data, use the wrong formula in their calculations and mistakenly assume that gas and electricity are the same price. They quote a figure of 115 baths which could be run from the savings. The correct figures are 56 baths if you are heating with gas, or just 16 if you are using electricity.

Smart Energy GB have published the calculations behind this advert at and it contains a litany of mistakes. They start by estimating the size of a bath, based on figures from the waterwise website. It looks as if Smart Energy GB has not checked the source behind this figure. It comes from a 1988 Defra report which is a recommendation to manufacturers make smaller baths, with the hope that this would reduce water use, targeting a volume of 80 litres by 2020. Instead manufacturers have generally made larger baths, with current baths holding between 85 and 110 litres for an average bath. Smart Energy GB ignore the real figures and use the projections, hence their starting point for the quantity of water to be heated is low.

Smart Energy GB then calculate the energy required to heat bathwater to 40°C, which is rather cool for a bath; 45°C is more common. If we use the smaller real bath capacity of 85 litres and the higher water temperature, the energy required to heat the water is 12.4kWh – about 20% higher than Smart Energy GB’s estimate of 10.0kWh.

Boilers are not 100% efficient, so this figure needs to be increased. Smart Energy GB assumes that boilers are 90% efficient, which is a figure they get from a Which webpage on choosing a new boiler. The best, modern condensing boilers are this efficient, but many are not. The same page tells us that old, gas boilers are only 55% efficient and the UK still has many boilers which fall into this category. Once again, Smart Energy GB have not checked where their source figure comes from. Instead they have taken the Panglossian view that everyone has the smallest possible bath and most efficient possible boiler. The average boiler efficiency in Britain is probably around 75%, although that is may well be optimistic.

To find the real amount of energy required, you need to divide the energy needed to raise the temperature of the water in a perfect world by the boiler efficiency, i.e.

actual energy used = energy output required / boiler efficiency

which gives a figure of 16.6kWh. Smart Energy GB have come up with a bizarre formula, which implies they don’t understand percentages:

which is wrong, gives the wrong answer and shows they don’t understand what they’re doing. Applying this incorrect formula to their incorrect starting figure for the energy needed, they come up with a total of 11.0 kWh per bath, against the correct figure of 16.6 kWh. Which means they overestimate the number of baths you could get from the savings.

But the mistakes don’t stop here. There is a bigger problem with their calculations, which is that you almost certainly won’t save energy on your gas bill. There is some evidence that smart meters help save electricity, because you get an almost immediate indication of energy usage. The favourite example is showing how much your kettle uses, which is a good reinforcement prompt to remind you to reduce the amount of water you boil. For gas, you only get told the amount of energy used every half hour, so you won’t know whether it was used by the oven for cooking breakfast, hot water for clearing up the mess in the kitchen afterwards, heating the house or having your bath. Without a clear connection between cause and effect, there’s no nudge to promote behavioural change. And you certainly shouldn’t take your In Home Display into the bathroom to try and work out your bathwater cost. Yet BEIS and Smart Energy GB keep on insisting that gas savings will happen, despite a dearth of evidence from anywhere else in the world. So, we should ignore any gas saving in the calculations.

If we only use the average electricity savings of 77.78 kWh per year, and divide that by the 16.6 kWh needed for each bath, then that would mean we’d saved enough for 17 baths. If we used the money from that saved electricity to buy gas to heat our water, we’d have enough for an annual 276 kWh, giving us 57 baths. Both of these figures are considerably below Smart Energy GB’s estimate of 115.

Smart Energy GB also forget to mention that you will only have a hope of saving energy if you use the In Home Display that is supplied with the smart meter. These can consume up to 0.6W, which is 14.4 Wh per day, or 5.26 kWh per year. This is additional electricity usage you pay for whether or not you make any savings. It means that the real electricity saving is only 72.5 kWh per year, so you would only be able to have 16 baths powered by electricity. The cost of running the In Home Display for a year is an equivalent cost to consuming 15.5 kWh of gas, which, if you heat your water with gas, means you’d only have saved enough to have 56 baths.

This advert also shows Smart Energy GB’s blindness about consequential costs. Harping on about the energy cost of a bath diverts people’s attention from the cost of water resources. If you use gas to heat your water, then the cost of water for the bath is likely to be greater than the cost of heating it. In her blog, Nicola Terry points out that whilst the gas to heat it would cost you 15.1p, the cost of the water is 20.5p. As security of water supply is as important as security of energy supply, it is dangerous to promote one without considering the effect on the other.

In this advert, Smart Energy GB attempts to demonstrate how, if the whole nation got a smart meter, we could save enough energy to power Manchester, Liverpool and Newcastle for a whole year. Except that they get their calculation wrong. It woudn’t be enough.

This calculation should be so easy that a school child could do it. As a starting point, if every house is saving 2% of their energy, you just need to calculate 2% of the total number of homes, (26,437,700), which gives you a figure of 528,754 homes.

That’s too easy for Smart Energy GB. Instead they use their estimate of the average saving per household of 354kWh and multiply that by the number of homes. Which would be fine if they didn’t make the schoolboy error of rounding up a number in the middle of the calculation. If the number of homes you’re using has six significant digits of precision, so should every other number you use in the calculation. But instead of using 353.800 kWh, they round it up to 354kWh, so they overestimate the number as 529,053 homes. It’s not a big difference, but it’s typical of the lack of attention we have come to expect from Smart Energy GB.

However, that’s still wrong, as the calculation is based on the fact that every household in Britain will save 2%. If they all save 2%, each home will only be using 17,336 kWh, rather than 17,800 kWh each year. This means that the amount of energy saved will now power even more homes – the true figure is 539,545, which is 2%, plus an additional 2% of that 2% (to reflect the fact that annual consumption has reduced) of the total number of homes.

Even with a figure that’s bigger than the one Smart Energy GB have come up with, it still doesn’t power Liverpool, Manchester and Newcastle. They used BEIS’ 2016 figure for average energy use, but used the older 2011 census for their housing numbers. All three cities have published more recent figures, indicating growth in the housing stock since 2011. In Liverpool in 2106 there were 221,806 dwellings, in Manchester in 2016 there were 226,240 and a more recent 2017 figure for Newcastle is 121,000, making a total of 569,046. So even with a correct figure of 539,545 homes which could be powered by the energy savings, it’s not quite enough to power Liverpool, Manchester and Newcastle.

In fact, the real picture is slightly worse, because of another omission. To make the 2% saving, each house will need to use its In Home Display, which consumes around 5.26 kWh per year of electricity, pushing the new annual household average up to 17,341 kWh. It’s only a minor change, but it knocks the total down to 539,381 homes, which still means that Smart Energy GB’s headline is a lie.

Whilst there’s not much difference in these absolute numbers, it is shocking that an organisation charged with teaching the nation about energy savings can’t do basic school mathematics and then uses mis-matched data to try and make a point. That is bad science and duplicitous. What is frightening is that Smart Energy GB openly display their lack of numeracy by publishing these incorrect calculations and outdated data sources, as if it is something to be proud of. They should not be permitted to advertise until they can show that they are competent.

In this advert, Smart Energy GB attempts to demonstrate how, if the whole nation got a smart meter, each household could save enough energy each year to charge an iPhone for 177 years. The problem is that they’ve got their calculations wrong. The actual figure for a current iPhone is around 16 years. If your phone has a larger screen it might only be 6 years.

Their first problem is that they don’t understand how battery charging works. They take the capacity of an iPhone4 battery (1.800 Ah) and assume the battery and charging is 100% efficient. Real life is different.

Their figure for battery capacity is for a 2010 iPhone, which has a 1,420 mAh battery. Over time, batteries tend to get bigger and the more recent iPhone 6 has a slightly larger capacity of 1,810 mAh, which would be a better starting point. To convert this to kWh, Smart Energy GB multiply the 1,420 mAh by the battery voltage of 3.7V, forgetting that this is the operating voltage. It is charged from a 5V supply. This miscalculation gives them a capacity of 5.254 Wh, when it should be 9.05 Wh. Some phones use a buck converter to make this more efficient, but there are invariably other inefficiencies such as over-charging, so it’s probably optimistic.

Smart Energy GB also assume that the charger is 100% efficient – in practice they are around 85% efficient. They also think that every joule of energy that goes into a battery comes back out. It doesn’t – you typically need to put in at least 110% of the battery capacity when the battery is new and 120% or more when the battery is six months old. Factoring these in, and being very optimistic, the energy needed to charge the phone each day is 12.530 Wh, not Smart Energy GB’s 5.254 Wh. So they’re already out by more than a factor of two.

The second problem is that they assume that energy savings will be made equally on electricity and gas. (In this they follow BEIS’s view, although there is no evidence that smart meters help save gas.) If we exclude gas savings, the energy savings should be restricted to the annual average household electricity usage of 3,889 kWh. 2% of that is 77.8 kWh. The annual consumption of our iPhone 6 is 12.530 x 365 Wh, which is 4.572 kWh to charge it once a day for a year. Compare that to the overall 77.8kWh saving and you’ll only be able to charge it for 17 years, not the 177 years that Smart Energy GB claim. In other words, they’re exaggerating by a factor of ten.

In the unlikely case that users did save energy by reducing their gas consumption, Smart Energy GB still get their figures wrong. To the best of my knowledge, no company sells a gas powered phone charger, so the money saved from the gas savings would need to be used to buy electricity. Smart Energy GB’s calculations forget that electricity is more expensive that gas. One kWh of gas costs around 4.4 pence, depending on where you live, whereas for electricity it costs about 13p. So the money you would save from a 2% reduction in gas usage would only buy you an additional 93.4 kWh of electricity, not the 276 kWh that Smart Energy GB use in their calculation. So, if you save gas as well as electricity (which you almost certainly won’t), you’d only be able to purchase enough energy to charge your iPhone for 38 years – still much less than their headline figure of 177 years.

If you think they couldn’t get anything else wrong, think again. Smart Energy GB forget to mention that you will only have a hope of saving energy if you use the In Home Display that is supplied with the smart meter. These can consume up to 0.6W, which is 14.4 Wh per day, or 5.26 kWh per year. This is additional electricity usage you pay for whether or not you make any savings. It means that the real annual electricity saving is only 72.5 kWh per year, so you would only be able to charge your iPhone 6 for 16 years.

The trend for larger phones, such as the Galaxy A9 is seeing batteries get bigger, with many now coming in at over 5,000 mAh. If you had one of these phones, then you’d only be able to charge it for around 6 years.

In this advert, Smart Energy GB attempts to demonstrate how, if the whole nation got a smart meter we could save enough energy to power Manchester, Cardiff and Aberdeen for 365 days. Except that they get their calculation wrong. We’d be able to power them for 406 days. Although that’s not far away from the headline, it’s pure luck, as Smart Energy GB’s calculations are wrong.

This calculation should be so easy that a school child could do it. As a starting point, if every house is saving 2% of their energy, you just need to calculate 2% of the total number of homes, (i.e. 2% of 26,437,700), which gives you 528,754 homes.

That’s too easy for Smart Energy GB. Instead they use their estimate of the average saving per household of 354kWh and multiply that by the number of homes. Which would be fine if they didn’t make the schoolboy error of rounding up a number in the middle of the calculation. If the number of homes you’re using has six significant digits of precision, so should every other number you use in the calculation. But instead of using 353.800 kWh, they round it up to 354kWh, so they overestimate the number as 529,053 homes. It’s not a big difference, but it’s typical of the lack of attention we come to expect from Smart Energy GB.

However, that’s still wrong, as the calculation is based on the fact that every household in Britain will save 2%. If they all save 2%, each home will only be using 17,336 kWh at the end of the first year of savings, rather than 17,800 kWh. This means that the amount of energy saved will now power even more homes – the true figure is 539,545, which is 2%, plus an additional 2% of that 2% (to reflect the fact that annual consumption has reduced) of the total number of homes.

In fact, the real picture is slightly worse, because of another omission. To make the 2% saving, each house will need to use its In Home Display, which consumes around 5.26 kWh per year of electricity, pushing the new annual household average up to 17,341 kWh. It’s only a minor change, but it knocks the total down to 539,381 homes.

To make their headline marketing point, Smart Energy GB then try to find a group of cities which has that number of homes. For an advertising campaign running through the summer of 2018, they used source data for the number of homes from the 2011 census, but base the energy consumption on data which BEIS published in 2016. All three cities have published more recent figures, indicating growth in their housing stock since 2011. In Manchester in 2016 there were 226,240 dwellings, in Aberdeen in 2017 there were 106,749 and the same year Cardiff reported 151,200, making a total of 484,191. That means that these three cities would not run for just 365 days on the national energy savings, As Smart Energy GB claim – they’d actually run for 407 days.

Whilst there’s not much difference in these absolute numbers, it is shocking that an organisation charged with teaching the nation about energy savings can’t do basic school mathematics and then uses mis-matched data to try and make a point. That is duplicitous. What is frightening is that Smart Energy GB openly display their lack of numeracy by publishing these incorrect calculations and outdated data sources, as if it is something to be proud of. They should not be permitted to advertise until they can show that they competent.

That’s it folks. Probably around £50 million of your money spent on fake headlines by an unaccountable quango. Please complain. Because Smart Energy GB are probably already drafting a request for a further £100 million for next year’s misinformation. We deserve something better.

I agree that this shouldn’t necessarily be the case, but I did some measurements on three phones I had lying around and they seemed to do exactly this. One in particular appeared to go into a constant current mode for most of the charge cycle, with something warming up the phone, suggesting it was dissipating the additional power rather than using a more efficient buck converter chip. All three had batteries that were at least a year old. I looked at the energy input required to take the battery from a starting point of between 10 and 15% to full, according to the phone’s display, calculated as voltage x current x time. The efficiencies I saw were 60%, 63% and 76%, so I’m probably being kind in my calculations. As these were measured using a bench power supply at 5V, they don’t include the inefficiency within a USB charger. Equally, they don’t allow for anything clever that might be negotiated between a phone and the manufacturer’s matched chargers, although I suspect that few people use the “right” charger 100% of the time.
It’s always possible that I have a poor selection of cheaper phones, but I’m probably not unrepresentative in not buying the most expensive ones.

If you look at the specs from companies like Dialog Semi, they imply that you should be able to get 94 – 96% efficiency when running from 5V, but I suspect this isn’t a priority for phone vendors. Their main concerns are power management once the battery is charged and speeding up the charging process. Both of those have an impact on user experience, whereas the charging efficiency doesn’t.

“no deliberate attempt to mislead”…really? you believe that….? THEY ARE TRYING TO SELL THESE THINGS TO THE MASSES….THEY’RE NOT GOING TO TELL YOU THAT THEY CAUSE CANCER AND GIVE THE STATE THE ABILITY TO RECORD ANYTHING AND EVERYTHING YOU DO IN YOUR OWN IN FULL 3D HOLOPORN REGARDLESS OF WHETHER YOU’RE WEARING CLOTHING OR NOT….

and i didn’t read the whole article….but you really believe they’re going to charge people LESS for electricity just for having one of these things installed? electricity is going to cost EXACTLY the same surely? + they will have to factor in the costs of these ‘things’, prices will increase…then there is also the possibility of them being held liable when they explode and burn houses down etc….so that will have to be paid for, as well as the wider cost to the economy in having to replace all that is damaged never mind the fact that the slaves inside can’t work anymore as they’re seriously injured or burnt to death….

+ these things run on electricity? how can something that runs on electricity decrease your usage? the whole thing is absurd to my mind and the morons are blindly falling for it….

Installing smart meters (not so smart meters) does not save any money, they will charge you for the unit and installation hidden in your bills.

The user will have to decide when to reduce consumption to save any money, smart meters on their own cannot save you any money unless the user stops using the energy and you do not need a meter to reduce your usage.

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About Creative Connectivity

Creative Connectivity is Nick Hunn's blog on aspects and applications of wireless connectivity. Having worked with wireless for over twenty years I've seen the best and worst of it and despair at how little of its potential is exploited.

I hope that's about to change, as the demands of healthcare, energy and transport apply pressure to use wireless more intelligently for consumer health devices, smart metering and telematics. These are my views on the subject - please let me know yours.

Essentials of Short Range Wireless

A helping hand for wireless designers

Adding wireless connectivity to a product is a major challenge for any designer. There are so many new concepts, and a plethora of suppliers claiming they’ve solved them for you. I’ve tried to distil 20 years of experience into this book to help you get over the pitfalls, ask the right questions and make sure you understand the answers.